<p><img src="https://static3.businessinsider.com/image/606456896183e10019819732-792/GettyImages-1303919072.jpg" border="0" alt="Pfizer BioNTech COVID-19 vaccine" data-mce-source="Pete Bannan/MediaNews Group/Daily Local News via Getty Images" data-mce-caption="Pfizer BioNTech COVID-19 vaccine"></p><p></p><bi-shortcode id="summary-shortcode" data-type="summary-shortcode" class="mceNonEditable" contenteditable="false">Summary List Placement</bi-shortcode><p>Pfizer-BioNTech's COVID-19 vaccine was 100% effective at preventing COVID-19 infection in kids aged 12 to 15 in late-stage trial of more than 2000 participants, the company <a href="https://www.pfizer.com/news/press-release/press-release-detail/pfizer-biontech-announce-positive-topline-results-pivotal" target="_blank" rel="noopener">announced Wednesday.</a></p><p>"In participants aged 12-15 years old, [Pfizer's COVID-19 vaccine] demonstrated 100% efficacy and robust antibody responses, exceeding those reported in trial of vaccinated 16-25 year old participants in an earlier analysis and it was well tolerated," Pfizer said in a press release. </p><p>Pfizer said side effects were similar for 12 to 15 year olds as for those aged 16 to 25, but did not detail what they were. </p><p>As it stands, Pfizer's two-dose vaccine is authorized in 66 countries worldwide for those over 16 years old, including the US. </p><p>So far, more than 26.7 million adult Americans have been fully immunized with two doses of Pfizer's vaccine, <a href="https://covid.cdc.gov/covid-data-tracker/#vaccinations" target="_blank" rel="noopener">according to the Centers for Disease Control and Prevention (CDC).</a></p><p>Pfizer plans to submit the data to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) in order to request for emergency authorization of the vaccine. </p><p>Albert Bourla, Pfizer's chief executive officer, said: "We plan to submit these data to FDA as a proposed amendment to our Emergency Use Authorization in the coming weeks and to other regulators around the world, with the hope of starting to vaccinate this age group before the start of the next school year."</p><p>Pfizer started trials in 5 to 12 year olds on March 28. The company said Wednesday that it plans to initiate trials in 2-5 year old next week.</p><p><em>The story is developing. Check back for details.</em></p><p><a href="https://www.businessinsider.com/pfizers-covid-19-vaccine-is-100-effective-in-12-to-15-year-olds-2021-3#comments">Join the conversation about this story »</a></p> Click here to read full news..